A New Phenolic Compound Isolated from Semen Celosia cristata L.

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1 ORIGINAL ARTICLE Rec. Nat. Prod. 11:2 (2017) A New Phenolic Compound Isolated from Semen Celosia cristata L. Qiyan Li 1, Defu Hu 1, Riran Zhu 4, Peiming Yang 3, Man Wang *2 and Zhenliang Sun *2, 3 1 Health Food and Cosmetics Laboratory of Shandong Institute for Food and Drug Control, Jinan Shandong , China 2 Fengxian Hospital affiliated to Southern Medical University, Shanghai , China 3 State Key Laboratory of New Drug and Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, China State Institute of PharmaceuticalIndustry, Shanghai , China 4 Pharmaceutical Department of Shandong Province Hospital of Traditional Chinese Medicine, Jinan Shandong , China (Received May 31, 2016; Revised November 7, 2016; Accepted November 8, 2016) Abstract: A new phenolic compound, named 3-geranyl-2,5-dihydroxy-benzaldehyde (1), together with seven known chalone derivatives (2 8) has been isolated from the seeds of Celosia cristata L. Their chemical structures have been elucidated by spectroscopic analysis. All these compounds (1 8) were isolated from C. cristata for the first time. Keywords: Celosia cristata L.; phenolic compound; chalone derivatives ACG Publications. All rights reserved. 1. Introduction The plant genus Celosia consisting of about 60 species in Amaranthaceae family, is native in subtropical and temperature zones of Africa, South America and South East Asia. Celosia cristata L. is a traditional medicinal herb used for the treatment of fatigue, atherosclerosis, leucorrhoea and osteoporosis [1]. Semen C. cristata is the seeds of C. cristata, commonly known as Ji Guan Hua Zi in Chinese, and has been utilized as a folk medicine for removing liver-heat, improving eyesight and clearing wind-heat. Phytochemical investigations of C. cristata have led to the isolation of several kinds of chemical constituents such as flavonoids, phenolic glycosides and saponins [2-4]. As part of our systematic phytochemical study on the genus Celosia of China plants, we have investigated the chemical constituents of Semen C. cristata. A new phenolic compound, together with seven known chalcone derivatives, was obtained from the EtOAc and n-butanol extracts. In this work, we report the process of isolation and elucidation of one new compound (1) and seven known chalone derivatives (2 8). * Corresponding author: hope1126@hotmail.com (Z. Sun); Phone: Fax: ; fengxianhospital@163.com (M. Wang); Phone: Fax: The article was published by Academy of Chemistry of Globe Publications Published 12/24/2016 EISSN:

2 167 Liet.al., Rec. Nat. Prod. (2017) 11: Materials and Methods 2.1 General 1D and 2D NMR spectra ( 1 H-NMR, 13 C-NMR, DEPT, HMBC, HMQC and 1 H- 1 H COSY) were obtained on a Bruker DRX-500 ( 1 H: 500 MHz and 13 C 125 MHz; Karlsrhe, Germany). Chemical shifts were given as δ values related to TMS as internal standard. Mass spectra were measured on a ThermoFinnigan MS spectrometer (Thermo-Finngan, Austin, TX USA). HPLC spectra were recorded on Agilent 1100 series (Santa Clara, CA, USA). Silica gel ( mesh) for column chromatography, and GF 254 for TLC was obtained from Qingdao Haiyang Chemical Co. Ltd. (Qingdao, China). 2.2 Plant material The seeds of C. cristata L. were purchased from Chengdu city, Sichuan Province, China, in September 2012, and identified by Prof. Mei-Li Guo from the Second Military Medical University School of Pharmacy (Shanghai, China). A voucher specimen ( A) was originally deposited in the State Key Laboratory of New Drugs, Shanghai Institute of Pharmaceutical Industry (Shanghai, China). 2.3 Extraction and isolation The air-dried seeds of C. cristata (5 kg) were extracted with ethanol (60% v/v) twice, 3 h for each time. The ethanol extract was concentrated under reduced pressure to yield a crude residue, which was then suspended in 4 liters of water and partitioned sequentially with ethyl acetate (EtOAc) and n-buoh to give three portions. The EtOAc extract (71.5 g) was subjected to silica gel column chromatography ( mesh) eluting with stepwise gradient of petroleum ether/etoac to afford five fractions (Fr.1 to Fr.5). Fr.3 (2.9 g) was subjected to silica gel column eluting with CH 2 Cl 2 /MeOH (25:1 to 10:1) to give three subfractions (Fr to Fr.3.3.3). The sub-fraction Fr was purified by Sephadex LH-20 eluting with MeOH to yield compounds 1 (5.5 mg), 2 (3.8 mg) and 3 (4.5 mg). Fr.4 (3.0 g) was subjected to silica gel column eluting with CHCl 2 /MeOH (20:1 to 5:1) to obtain two sub-fractions (Fr.4.1 and Fr.4.2). Compounds 4 (5.5 mg) and 5 (5.0 mg) were isolated after eluting the Fr.4.1 with MeOH using Sephadex LH-20 column. The n-buoh extract (40.0 g) was decolorized on a MCI gel (CHP 20P) column chromatography eluted with MeOH/H 2 O (0:100 to 100:0), yielding seven sub-fractions (Fr. A Fr. G). The sub-fraction (Fr. D, 3.5 g) was subjected to reversed phase silica gel column employing MeCN/H 2 O (23:77), yielding three portions (Fr. D1 Fr. D3). Further purification of Fr. D3 by Sephadex LH-20 (MeOH) gave birth to compound 6 (6.0 mg). The sub-fraction (Fr. E, 5.0 g) was chromatographed over reversed phase silica gel column. Successful elution of the column with MeOH/H 2 O (32: 68) yielded three portions (Fr. E1 Fr. E3) after removing the solvent. Fr. E1 was further separated by Sephadex LH-20 column chromatography eluting with MeOH to give compounds 7 (18.0 mg) and 8 (20.0 mg). Figure 1. Chemical structure and key 1 H- 1 H COSY and HMBC correlations of compound 1

3 3. Results and Discussion A new phenolic compound isolated from Semen Celosia cristata L. 168 Compound 1 was obtained as yellow amorphous powder, UV (MeOH): λ max (log ε), 228 (4.97), 265 (4.55), 365 (4.26), whose molecular formula was determined as C 17 H 22 O 3 by HR-ESI-MS (m/z, [M+H] + ; calc ), and its value of unsaturation was 7 (Figure 1). The IR spectrum displayed absorptions for hydroxyl (3350 cm -1 ), double bonds (1630 cm -1 ) and aldehyde group (2700 and 1700 cm -1 ). The 1 H NMR spectrum exhibited three methyl signals at δ ppm 1.69 (3H, s), 1.68 (3H, s) and 1.60 (3H, s), and also showed three methylene proton signals at δ 3.35 (2H, t, J = 7.5 Hz), 2.12 (2H, t, J = 7.2 Hz) and 2.07 (2H, t, J = 6.7 Hz). Two aromatic proton signals at δ 6.96 (1H, s) and 6.83 (1H, s) suggested the presence of a 1,2,3,5-substituted benzene ring. Two olefinic proton signals at 5.30 (1H, t, J = 7.3 Hz) and 5.10 (1H, t, J = 7.2 Hz) were observed in 1 H NMR spectrum. The appearance of a methine proton signal at 9.80 (1H, s) indicated the presence of an aldehyde group. The 13 C NMR and DEPT spectrum of compound 1 displayed 17 distinct signals, including three methyls, three methylenes, five methines and six quaternary carbons. With the aid of HMQC, HMBC and 1 H- 1 H COSY experiments, all the 1 H and 13 C NMR were assigned as shown in Table 1. The 1D NMR spectroscopic data of compound 1 showed a quite similar pattern with those of 3-farnesyl-2,5-dihydroxy-benzaldehyde [5]. The difference between them was lack of an isoprene group. In the HMBC spectrum of compound 1, crosspeaks of δ H 6.83 (H-6) with δ C (C-7) and δ H 9.80 (H-7) with δ C (C-2) suggested that the aldehyde group is directly connected to C-1. In the 1 H- 1 H COSY spectrum, cross signals between δ H 3.35 (H-1 ) and δ H 5.30 (H-2 ), δ H 2.12 (H-5 ) with δ H 2.07 (H-4 ) and δ H 5.10 (H-6 ), along with the long correlations of δ H 2.07 (H-4 ) to δ H 1.69 (H-10 ) and δ H 5.10 (H-6 ) to δ H 1.60 (H-8 ) and δ H 1.68 (H-9 ) indicated the presence of CH 2 CH=C(CH 3 )-(CH 2 ) 2 CHC(CH 3 ) 2. From HMBC spectral data, the correlations between δ H 3.35 (H-1 ) and δ C (C-2 ), (C-4), (C-3), (C-3 ), (C- 2) indicated that the CH 2 CH=C(CH 3 )-(CH 2 ) 2 CHC(CH 3 ) 2 group was located at C-3,which was also supported by the HMBC correlations of δ H 6.96 (H-4) to δ C 27.0 (C-1 ). On the basis of the above evidence, compound 1 was identified as 3-geranyl-2,5-dihydroxy-benzaldehyde. Seven known compounds were identified by comparing their spectral data with those reported in the previous literature as follows, cardamonin (2) [6], 2-hydroxy-4,6-dimethoxylchalcone (3) [7], 2,4 - dihydroxy-3,6 -dimethoxychalone (4) [8], 3-hydroxy-phloridzin (5) [9], sieboldin (6) [10], 3- hydroxyphloretin 4 -O-[4,6 -O-(s)-HHDP]-ß-D-glucoside (7) [11] and 3-hydroxyphloretin 4 -O-[3 - O-galloyl-4,6 -O-(s)-HHDP]-ß-D-glucoside (8) [11] (Figure 2). Table 1. 1 H NMR (500 MHz) and 13 C NMR (125 MHz) spectral data of compound 1 in CDCl 3 (δ in ppm and J in Hz) Position δ H δ C (s) (s) (t) (1H, s) (d) (s) (1H, s) (d) (1H, s) (d) (2H, t, J = 7.5 Hz) 27.0 (t) (1H, t, J = 7.3 Hz) (d) (s) (2H, q, J = 6.7 Hz) 39.7 (t) (2H, q, J = 7.2 Hz) 26.6 (t) (2H, t, J = 7.2 Hz) (d) (s) (3H, s) 25.7 (q) (3H, s) 17.7 (q) (3H, s) 16.1 (q)

4 169 Liet.al., Rec. Nat. Prod. (2017) 11: Figure 2. Structures of compounds 2 8 Acknowledgments This work is funded by Research Project of Shanghai Municipal Commission of Health and Family Planning (No ), and partly supported by Shanghai Fengxian District Science and Technology Project ( ), Shanghai Fengxian District Science and Technology Project ( ) and Shanghai No.6 People s Medical Group Project. Supporting Information Supporting Information accompanies this paper on References [1] Z.L. Sun, G.L. Gao, Y.F. Xian, J. Feng and Z.Y. Qiao (2011). A new hepatoprotective saponin from Semen Celosia cristatae, Fitoterapia 82, [2] Y. Wang, Z. Lou, Q.B. Wu and M.L. Guo (2010). A novel hepatoprotective saponin from Celosia cristata L., Fitoterapia 81, [3] S.M. Zhang, X.F. Wang, J. Feng and Z.L. Sun (2015). Chemical constituents of the seeds of Celosia cristata, Chem. Nat. Comp. 52, [4] A. Mroczek (2015). Phytochemistry and bioactivity of triterpene saponins from Amaranthaceae family, Phytochem. Rev. 14, [5] A.G. Ferreira, M. Motidome, O.R. Gottlieb, J.B. Fernandes, P.C. Vieira, M. Cojocaru and H. Gottlieb (1989). Farnesyl-homogentisic acid derivatives from Otoba parvifolia, Phytochemistry 28, [6] K.S. Ngo and G.D. Brown (1998). Stilbenes, monoterpenes, diarylheptanoids, labdanes and chalones from Alpinia katsun adai, Phytochemistry 47,

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